Tympanomastoidectomy surgery for chronic suppurative otitis media (CSOM) requires an understanding of the 3-dimensional anatomic structures of the middle ear. Although these structures can be evaluated radiologically, differences between CSOM and non-CSOM patients have not yet been determined, and the agreement between preoperative and intraoperative measurements has not been evaluated. This cross-sectional study was conducted at Cipto Mangunkusumo Hospital, Jakarta, Indonesia. The aim of this study was to evaluate differences in the temporal bone distances between CSOM and non-CSOM patients using computed tomography (CT) data from 30 consecutive cases and to evaluate the agreement between temporal bone distances measured using CT and intraoperative microscopy in 5 consecutive CSOM patients within a 9-month period. CSOM patients had smaller distances from the superior wall of the ear canal to two points on the tegmen, as well as a more acute sinodural angle and narrower aditus ad antrum. There was a good agreement between the temporal bone CT and intraoperative measurements of the distance from the posterior wall of the ear canal to the sigmoid sinus. © 2018 Institute of Physics Publishing. All rights reserved.